Hydraulic machine of axial piston type



arch 30, 1965 MOLLY HYDRAULIC MACHINE OF AXIAL PISTON TYPE 8Sheets-Sheet 1 Filed April 17, 1962 zozbsomm owmmm mama PowEQ N tINVENTOR.

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INVENTOR: has BY M, WWW

March 30, 1965 Filed April 17, 1962 IV J M2 WW March 30, 1965 H. MOLLY3,175,363

HYDRAULIC MACHINE OF AXIAL PISTON TYPE Filed April 17, 1962 v 8Sheets-Sheet 3 March 30, 1965 H. MOLLY 3,175,363

HYDRAULIC MACHINE OF AXIAL PISTON TYPE Filed April 17, 1962 8Sheets-Sheet 4 1' Q Q Q a a N w 2 N N g Q N N N '6 N O N 1 8 LL Q A n N2 IN V EN TOR:

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Mamh 30, 1965 H. MOLLY HYDRAULIC MACHINE OF AXIAL PISTON TYPE 8Sheets-Sheet 5 Filed April 17, 1962 INVENTOR: N-M W BY MAM W W5 Marsh30, 1965 H. MOLLY 3375,36

HYDRAULIC MACHINE OF AXIAL PISTON TYPE Filed April 17, 1962 8SheetsSheet 6 I. l X

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INVENTOR:

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March 3%, 1965 HYDRAULIC MACHINE OF AXIAL PISTON TYPE Filed April 17,1962 8 Sheets-Sheet 8 INVENTOR. lw'fi M BY H MOLLY HYDRAULIC MACHINE OFAXIAL PISTON TYPE mm? 30, f="

Filed April 17, 1962 United States Patent 31 Claims. (Cl. 60-53) Theinvention relates to hydraulic axial piston machines. As is well known,axial piston type machines have a cylinder block with axial cylinderbores in which pistons may slide, the pistons abutting an oblique diskinclined relatively to the axis of the cylinder block. With a relativerotary movement between the oblique disk and the cylinder block, thepistons execute a stroke. Now, the cylinders may be alternatinglyconnected with a suction and a pressure pipe over valves or acontrolling slide valve in such a manner that the arrangement acts as apump. On the other hand, oil under pressure may be fed to the cylinders,which oil acts on the pistons in such a manner that a relative rotarymovement between the oblique disk and the cylinder block is produced andthe machine operates as hydraulic motor. It is known to adjust theposition of the oblique disk relatively to the cylinder block in orderto thereby change the piston displacement and therewith the capacity ofthe pump or the motor speed, as the case may be.

It is known to combine a pump of this type with a correspondinglydesigned hydraulic motor. If the pump is being driven with an inputspeed n an output speed 12 is derived from the motor being supplied bythe pump. The ratio i= 2 may be changed through adjustment of theoblique disks. Such an arrangement is provided by a hydrostatic axialpiston transmission with constantly varying transmission ratio. Suchtypes of transmissions are applicable to many fields of technics, as, byway of example, for machine tool drives or for automobile or tractordrives. Such devicespumps, oil motors, transmissions-are consideredherein under the collective name hydraulic axial piston machines.

Hydrostatic 'aixal piston transmissions are known where the obliquedisks are fixedly arranged and one of the cylinder blocks is connectedwith the driving shaft and the other with the driven shaft. With suchtransmissions the total power is hydraulically transmitted. Since theefficiency of the hydraulic power transmission ratio is relatively lowand with known transmissions has a maximum of about 80% and,furthermore, from a maximum value the efficiency strongly decreasesagain as the transmission ratio i moves towards 1, such transmissionsare disadvantageous for many purposes. However, transmissions with powerbranching are also known, where, by way of example, a cylinder block isdriven by the driving shaft, the second cylinder block is stationarywith repect to the casing and the associated oblique disks are rotatingtogether with the driven shaft. Such transmissions have the property tothe effect that a portion of the power is entirely mechanicallytransmitted with essentially 100% efliciency. This portion of the purelymechanically transmitted power is zero for i=0 and becomes 100% for i=1.A more favorable elficiency behavior of the transmission results sinceonly a portion of the power is transmitted with the poorer hydraulicefficiency. In particular, the drop of the efficiency as i approches 1is avoided.

It is known to adjust the oblique disks of such axial piston machines bymeans of hydraulic auxiliary forces.

3,175,303 Patented Mar. 30, 1965 ice With known arrangements of thistype, the oblique disks are rotatably supported about an axis which isperpendicular to and intersects the rotational axis of the machine.

The known axial piston type machines are relatively complicated indesign. In particular, great ditliculties arise in adjusting the obliquedisks. With a known axial piston transmission with power branching(German Patent No. 1,052,766) the oblique disks are mechanically coupledwith each other and a simultaneous adjustment in opposite direction ofthe two oblique disks takes place with a complicated mechanism. Thisdoes not only lead to constructional difiiculties, increased cost andincreased susceptibility to failure, but also results in an unfavorabletransmission ratio versus path of adjustment characteristic. Othertransmissions with power branching adjust the rotating oblique diskswith cam means in an also rotating axially movable control bell. Thisconstruction, too, is most complicated.

It is a primary object of the present invention to provide simplifiedmeans of the adjustment of the oblique disks in hydraulic axial pistonmachines, especially in hydrostatic axial piston transmission.

The invention is based on the realization that a substantial difficultyof the known constructions lies in the fact that double acting adjustinggear is required for adjusting the oblique disks, that is to say, a gearwhich acts to provide a to-and-fro adjustment of the oblique disks. Withthe customary symmetrical positioning of the oblique disk relatively tothe associated pistons, the pistons do not exert any resetting forces onthe oblique disk with an adjustment of the same. This is due to the factthat the separating line between pressure chamber (tending to move thepistons into the cylinder block) and suction chamber (tending to movethe pistons out of the cylinder block) extends perpendicularly to theaxis of rotation of the system so that the oblique: disk is alwaysequally loaded with pressure exerted by the pistons on both sides of theaxis of inclination of the disk, on each side partly with pistonsconnected to the pressure side and partly with pistons connected to thesuction side. Thus, the pistons do not exert a resulting inclinationaltorque on the oblique disk which might become effective as resettingforce with reference to an adjusting movement of the disk.

According to the invention, provision is made that with a rotation ofthe oblique disk a common axial displacement of the axial pistons takesplace and that a single-acting auxiliary hydraulic force becomes axiallyelfective against the resetting force of the axial pistons. Through acommon axial displacement superimposed on the inclinational movement ofthe disk a resetting force is produced counteracting the inclinationaland axial movement so that a single-acting auxiliary hydraulic forcewill be sufficient. With a decrease of the auxiliary force the obliquedisk automatically moves responsive to the influence of the resettingf-orce exerted by the pistons. The design is substantially simplified.

Various adjusting transmissions are possible where an axial displacementis superimposed upon an inclinational movement of the oblique disk. Thearrangement, however, becomes particularly simple if the oblique disk ispivotally supported at an off-center axially fixed point and inclinablethereabout through auxiliary hydraulic force.

it is expedient to provide a follow piston arrangement for theadjustment where an axially movable control sleeve on the one handprovides a follow piston system as pick-up piston with a hydraulicadjusting piston and at the same time carries pressure means for theadjusting cylinder. This results in a very simple adjusting device. Sucha device could also be applicable for other simpleacting hydraulicadjusting gears other than in axial piston machines.

It is a further object of this invention to simplify and improve thedesign of hydrostatic axial piston transmissions relatively to knownconstructions. The invention provides for a basic design of atransmission with two coaxially arranged axial piston and oblique disksystems one of which acts as pump and the other as motor, where, inaccordance with the invention, one adjusting cylinder body, oneadjusting piston, one oblique disk and one cylinder block each areslipped over and mounted upon a central shaft on both sides of adouble-acting operating slide valve. Such a transmission may be designedas power-branched transmission in that one cylinder block is drivenwhile the other is stationarily arranged with respect to the casing, andthe central shaft with which the oblique disks rotate provides thedriven shaft. It may, however, also be a transmission with purelyhydraulic power transmission where one cylinder block is connected witha driving shaft and the other cylinder block is connected with thedriven shaft through forkshaped or bell-shaped driving members grippingaround the adjusting cylinder bodies and with the oblique disks outside,While the adjusting cylinder bodies and oblique disks are supported on astationary central shaft and the operating slide valve is supportedstationary with respect to the casing. In both cases a simple and cleardesign results.

With a transmission of the type herein described, an adjustmentpossibility particularly simple with the described follow pistonarrangement can be provided for the oblique disks by arranging thecontrol sleeve for guidancev in a groove of the central shaft. Itthereby becomes possible for one control sleeve to control twosingle-acting adjusting pistons for the adjustment of the two obliquedisks of an axial piston system with one part acting as pump, and onepart acting as motor, a dead stroke of the control sleeve being providedso that one adjusting piston executes its full stroke, before the otheradjusting piston starts its stroke.

A further most advantageous design for adjusting the oblique disks is.obtained, if, as hereinafter described with reference to an alternativeembodiment of the invention the oblique disk is inclinationally andaxially movably arranged on a central guide member and supported on twosupporting members parallel to each other and transversely relatively tothe guide member, one of which is supported in an adjusting cylinder forthe auxiliary hydraulic force and the other in an adjusting pistonsliding therein. It is expedient to have the supporting members designedas rotatably supported half-cylindrical bolts on the plane surface ofwhich the oblique disk is supported. The guide member may be provided bya central shaft.

A static balancing of the oblique disk may be provided. It is expedientto this end to have the oblique disk annularly surrounding the guidemember supported with a spherical inner surface on a toroidal ring withcorrespondingly spherical surface, being axially movably guided on theguide member. The oblique disk may thereby be inclinationally supportedabout its center of gravity on the rotational axis. Besides, this lattercase offers the advantage that the load of the oblique disk exerted bythe pistons is distributed on a relatively wide annular area of theoblique disk over a period of time. The contact surface of the obliquedisk may be supported over thrust bearings with several rollers adjacenteach other and thereby a smaller medium bearing load and a longer lifeis obtained.

In order to render possible the mounting of the oblique disk on thespherical toroidal ring, the oblique disk may have axial groovesopposite each other at the inside, having the width of the toroidalring. Then, the toroidal ring is moved in the grooves into the centralopening of the. oblique disk body, until the centers of the toroidalring surface and of the spherical inner surface of the oblique disk bodycoincide. At this point, however, the toroidal ring may be rotated asdesired relatively to the oblique disk body and the grooves, since thenone spherical surface slides in the other. Then, the toroidal ringtogether with the oblique disk secured thereupon may be drawn onto thecentral guide member.

Another still simpler constructional solution consists in that theannular oblique disk is supported with a cylindrical inner surface on aspherical torus. This typeof support, too, ermits an inclinationalmovement of the oblique disk relatively to the axis and an axialmovement of the oblique disk with the cylindrical inner surfacerelatively to the spherical torus. This has the advantage of greatersimplicity. A shortcoming, however, is that the center of gravity of theoblique disk is not always exactly positioned on the axis. so that acertain static unbalance may be manifested. It can, however, be shownthat such resulting shortcoming is so insignificant as to be negligible.

With this arrangement, too, a dynamic unbalance is occurring. Therefore,with inclined oblique disk a torque caused by the centrifugal forces isacting. on the oblique disk, which tries to adjust the oblique disk tobe perpendicularly arranged relatively to the rotational axis. Normally,this torque is counteracted by forces exerted by the pistons and theadjusting piston. It may, however, occur that the working pressuresuddenly drops. By way of example, this may occur if a hydrostatic axialpiston transmission designed in accordance with the invention initiallyhas to transmit a great torque with a high reduction ratio and thistorque suddenly disappears or is great ly reduced, without the reductionratio changing immediately. This case occurs, for example, if a tractorwith such a transmission slowly moves up a hill (high reduction ratio,great torque) and at the top the torque to be transmitted suddenlydecreases. Then, the working pressure in the transmission breaks downuntil the transmission ratio is possibly correspondingly changed throughadjustment of the transmission, the tractor moves faster and a highertorque again occurs. Similar conditions may also arise with otherapplications, for example also if the gas supply is throttled with fulldriving speed.

Now, it is customary to feed operating oil for makeup and controlpurposes under a selected pressure, to the system by means of anoperating oil pump and pressure regulating means. This operating oilpressure is present as well on the suction side of the axial piston-typemachine as also, at least, on the pressure side. The operating oilpressure does not exert a torque, since it exists both on the suctionside and on the pressure side of the axial piston machine. Thetransmitted torque determines the differential of working pressure andoperating oil pressure. Therefore, with minor torque the workingpressure is only relatively little above the operating oil pressure. Theforce exerted by the operating oil pressure on the axial piston isnormally not in a position, now to overcome the torque exercised by thecentrifugal forces on the oblique disk. The oblique disk can thereforestraighten out so that the non-positive connection with the supportingmembers gets lost. The cylinder block, too, is non-positively pressedagainst the controlling slide valve by the working pressure, the forceof contact pressure supporting at the oblique disk over the axialpistons.

In order to avoid these undesirable phenomena, the invention furthermoreprovides, that reversing means impinged upon by the working oil pressureof the machine are provided'which respond with a decrease of the workingoil pressure below a minimum value and whereby a higher theoreticalvalue of the pressure regulating means is adjustable. If then, thetorque decreases and also the Working pressure is correspondinglyreduced, an automatic reversal to a higher operating pump pressureresults. The working pressure is thereby correspondingly increased,since the transmitted torque is determined by the differential ofworking oil pressure and operating pump pressure. This increasedpressure, then, is in a position again to overcome the tilting torquecaused by the centrifugal forces.

Centrifugal forces act on the piston similar to the forces that act onthe inclined oblique disk. Since with inclined oblique disk the pistonson one side protrude further from their cylinders than on the oppositeside, torques are occurring which try to tilt the cylinder block. Thecentrifugal forces that act on each individual piston, are rotating withthe cylinder block speed. However, the to-and-fro movement of thepistons takes place according to the inclination of the oblique disk andwith the speed of same, also the torque applied to the cylinder block isa rotating force. The points of contact of the centrifugal forces aremoved in axial direction in accordance with the inclination of theoblique disk.

The support of the cylinder block is normally not adapted to receivethis torque, since the cylinder block must flatly and tightly abut theoperating slide valve surface and must therefore be able to alignrelatively thereto. The very highly adjusted axial relief of theoperating slide valve surface does not stand an additional tiltingstress.

in a further modification of the invention, the diameter of theoperating slide valve surface is increased by the torque, which isexerted on the cylinder block by the centrifugal forces of the pistons,relatively to the diameter required for the function of the operatingslide valve alone, and a pressure field arranged on the enlargedoperating slide valve surface, which is impinged upon by a pressureproportional to the working pressure and with the residual force of theaxial relief constitutes a momentum which is counteracting to thecentrifugal force momentum of the pistons. Therein the fact is utilizedthat the operating slide valve always rotates with the oblique disks oris stationarily arranged depending on what type of transmission isinvolved and that therefore the pressure field on the operating slidevalve surface is synchronously rotating with the centrifugal forcemomentum and can compensate the same.

As a rule with transmissions of the type herein described, an operatingoil pump is provided which maintains a certain minimum oil pressure alsoon the suction side in the hydraulic system and balances oil leakagelosses. A particularly advantageous oil conduction is provided if theoperating oil pump annularly surrounds the shaft and feeds operating oilunder pressure inwardly into an operating oil channel extending alongthe shaft. From this channel the oil may then be tapped at any desiredpoint and fed into the operating slide valve. Thereby, it isinsignificant whether the operating slide valve is rotating with theshaft or whether these two parts are stationarily arranged. Operatingoil pipes extending at the outside are omitted. The arrangement may beone in which the shaft consists of a central part and a sleeve enclosesthe same a spaced distance apart therefrom and between these members anannular operating oil channel is provided. With such a symmetricalarrangement the oil may be supplied or discharged in any desireddirection.

With a transmission wherein in the known manner the operating oil systemis in connection with the outlet over an elastically suspended pressurecontrol valve, provision can be made that the operating oil flowingthrough the pressure control valve flows off in axial channels along theshaft to both sides below the cylinder block and under the influence ofcentrifugal force is sprayed against the oblique disks and cools thesame. It is expedient to have at least one of the oblique diskssurrounded by a cylinder the inner surface of which is coated with astrongly absorbent material. Thereby, a thorough, continuouspurification of the oil from undesirable dirt particles is effectedwhereby the life of the transmission can be substantially increased.Pilot-cloth of the kind of Meltoncloth proves to be advantageous asabsorbent material. The absorbent material may be exchanged from time totime.

Illustrative embodiments of the invention are presented in the drawingsand described as follows:

FIG. 1 is a longitudinal section through a powerbranched hydrostaticaxial piston transmission according to the invention;

FIGS. 2 to 5 diagrammatically show different positions of the obliquedisks for attaining different transmission ratios:

FIG. 6 is a cross-sectional view taken along line VI VI of FIG. 1 andshows the operating oil pump of the transmission;

FIG. 7 is a cross-sectional view through the operating slide valve takenalong line VII-VII of FIG. 1;

PEG. 8 is a cross-sectional view through the stationary cylinder blockof the transmission taken along line VIII VIII of FIG. 1;

FIG. 9 is a longitudinal view, partly in section, of a hydrostatic axialpiston transmission without power branching;

FIG. 10 is a cross-sectional view taken along line X-X of FIG. 9;

FIG. 11 is a detail view, in cross section, showing another embodimentof adjusting mechanism;

FIG. 12 is a longitudinal section showing the driving side of anotherform of hydrostatic axial piston transmission embodying the invention;

FIGS. 13 and 14 are detail views, in cross section, showing the obliquedisk of the transmission of FIG. 12 with its adjusting gear and thecylinder block for different positions of the oblique disk;

FIG. 15 is an exploded view of the transmission of FIG. 12 illustratingthe parts thereof in perspective and partly in section;

FIGS. 16 and 17 are cross-sectional views in different planes throughthe operating slide valve in the transmission of FIG. 12;

FIG. 18 is a detail view, in cross section, showing somewhat modifiedarrangement of the corresponding parts of FIG. 12;

FIG. 19 is a longitudinal section through an axial piston transmissionembodying a further modification of the invention;

FIG 20 is a perspective view, partly in cross section of the operatingoil pump of the transmission of FIG. 19, and

FIGS. 21 and 22 are detail views, in cross section of the operatingslide valve of the transmission of FIG. 19.

Reference is first made to FIGS. 1 to 8 wherein a transmission withpower branching is shown, that is, a transmission where a portion of thetransmitted power is directly mechanically transmitted and only aportion of the power is transmitted as hydraulic power. Referencenumeral 1 designates a generally cylindrical casing body which is closedat its two front ends by hearing plates 2, 3 screwed to the casing body1 by screws 4. In the bearing plate 2 a driving shaft 6 is supported ina ball bearing 5. The driving shaft 6 has splines 7 for coupling adriving machine not shown, for instance a diesel engine. At its innerend the driving shaft 6 has an enlarged portion 8 with a centraldead-end bore 9. In this bore one end of the driven shaft 12 issupported by means of a roller bearing 11. The driven shaft 12 extendsthrough the whole transmission and is supported in the bearing plate 3by means of a roller bearing 13. A gear 14 is keyed with the protrudingend of the shaft 12 for connection with the load and is secured by a nut15 and a spring washer 16.

An operating slide valve 17 is slipped over and onto the shaft 12 fromthe right and abuts a shoulder 18 of the shaft. The shaft 12 has a longlongitudinal groove 19 (see also FIG. 8). A spline 21 of the operatingslide valve 17 is engaged in said groove 19 so that the slide valve isnon-rotatably keyed with the shaft 12. Reference numeral 22 designatesan adjusting sleeve which is axially movable in central recesses 23 and24 of the operating slide valve 17 and of a cylinder block 25, as willbe described hereinafter. The cylinder block 25 sealingly abuts theright face 25 of the operating slide valve 1'7.

The cylinder block 25 has axial bores in which pistons 27 reciprocate.The pistons 27 abut an oblique disk or swash plate assembly generally 28or, more accurately, a race 33 forming a part of and journalled in disk28. The oblique disk 28 comprises a base body 29 of semicylindricalbasic shape with a cylindrical guide surface and a central opening 31across which the shaft 12 extends. The opening 31 is wide enough topermit a range of inclination of the body 29 relatively to the shaft 12.The race 33, engaged by the pistons, is supported on the base body 29 bymeans of a thrust bearing 32.

A sleeve 54 surrounds and is secured to driven shaft 12. This sleeve hasa radially projecting shoulder 35 which serves as a pivot about whichthe oblique disk or swash plate assembly may move in inclination. Thebase body 29 of the swash plate assembly is eccentrically supported bythis shoulder without the two having a relative rotational movementabout the axis of driven shaft 12. Sleeve 34 tightly engages shaft 12and with its one end abuts an axial collar 36 of the operating slidevalve 17. A sleeve 22 is arranged to slide axially on the collar 36 andthe end of sleeve 34. At groove 19 the collar 36 and the end of sleeve34 have a longitudinal slot 37 through which a projecting single spline33 of the adjusting sleeve 22 extends into the groove 19, as can be seenin FIG. 8. At the other end of sleeve 34 is a spring ring 39 engaged ina groove in the driven shaft to prevent the sleeve from moving axiallyto the right in FIGURE 1'. Therefore, sleeve 34 is rigidly connected 5with shaft12 just as is. the operating slide valve 17 The cylinder block25 is supported for relative rotation on sleeve 34 by means of a needlebearing 41.

The base body 29 of the oblique disk or swash plate assembly issupported with its cylinder surface in a corresponding cylindrical guidesurface 42 of an adjusting piston 43. The adjusting piston 43 isnon-rotatably guided in an adjusting cylinder 44 being provided in acup-shaped adjusting cylinder body 45. The adjusting cylinder body 45has a collar 45 which is keyed to driven shaft 12 by means of groove 19.Through this collar 45 the shaft 12 is supported in the bearing 13.Piston 43 has a spline 47 which protrudes into the groove 19 for reasonswhich will be specified hereinafter. For the transmission of torque itis connected at its periphery with the cylinder body 45 which has axialslots 48 into which radial projecting parts 49 of the piston 43protrude. For sealing the piston 43 in the cylinder 44 an O-ring 51 isprovided.

The cylinder block 25 is held non-rotatably in the casing 1. This isachieved by means of a hollow cylinder 52 which surrounds oblique disk28 and the adjusting cylinder body, 43. Cylinder 52 has two internaltoothings 53, 54 at its two ends. These internal toothings 53, 54- arein clearance engagement with two toothings 55 and 55, respectively, ofthe fixed bearing plate 3 and of the cylinder block 25, respectively.Thus, the cylinder block is held against rotation. The clearance,however, ensures that the cylinder block can satisfactorily alignrelatively to the. face 25 of operating slide valve 17.

At the pump end of the transmission, (the left end in FIGURE 1), acylinder block 58 abuts face 57 of operating slidevalve. 17. Thecylinder block 58, just as the cylinder block 25, has axial cylinderbores 59 in which pistons 61 reciprocate. Pistons 61 engage an obliquedisk structure or adjustable swash plate assembly which is generallydesignated with reference numeral 62. Similarly to the oblique disk 28,the oblique disk 62; comprises a semi-cylindrical base body 63 with anopening (:4 for passage of shaft 12. Opening 64 is widened so as to perniit inclinational movement of body 63. A race 65, which pistons 61abut, is movably supported in the base body 53 by means of a thrustbearing 65.

A sleeve 67 is mounted on shaft 12, being axially secured by a springring 68. Similarly to sleeve 34-, said sleeve 67 has a radiallyprojecting shoulder 69 which is engaged as a pivot by the oblique diskbase body 63 as an eccentric stop about which the disk may be moved ininclination. The oblique disk base body n3 is supported with itscylinder surface in a corresponding cylindrical bearing surface 71 of anadjusting piston 72. The adjusting piston '72 is guided in a cylinder73, of a cylinder body 74. The cylinder body 74 is keyed with drivenshaft 12 at '75. Piston 72 is provided with radially projecting parts 76which are guided in longitudinal slots 77 of the cylinder body 74. Thesealing of the adjusting piston 72 in the cylinder 73 also is effectedby an O-rin 73 inserted in an annular groove of piston 72.

The enlargement 3 of the driving shaft 6 flares out into a bell-shapedradial flange 79 having an external peripheral toothing 81. The cylinderblock 58 has an external tootning 32. A hollow cylinder 33 whichencloses the cylinder block 58, the oblique disk 62 and the adjustingcylinder body 74 is provided with internal toothings 84, at its twoends, which are in clearance engagement with the toothings 81, 82respectively. Consequently, the cylinder block 58 is driven by thedriving shaft 5. Here, too, the clearance in the toothings makespossible an exact engagement of the cylinder block 58 with the face 57of operating slide valve 17.

Thus, with the design as described the cylinder block 53 rotates withthe driving shaft. The cylinder block 25 is stationary with respect tothe casing. The oblique disks 28 and 62 with the associated adjustingcylinders and pistons 43, 45 and 72, '74 respectively, and the sleeves34 and 67 as well as the operating slide valve 17 rotate with drivenshaft 12.

A tubular control slide 86 is arranged in groove 19 and is fixedlymounted in the projecting spline 33 of sleeve 22. Piston 43 has an axialbore 87 in a portion of spline 47 thereof which extends into groove 19,into which bore an open end of the control slide 85 protrudes. The endof the control slide has an enlargement 88 which sealingly slides inbore 87 as a hollow piston. A channel 91 and lateral opening 89 providesconnection of the bore 87 with the adjusting cylinder chamber 92. In asimilar manner, piston '72 sliding on a reduced diameter of shaft 12,has an axial bore 93 in a portion thereof which extends into groove 19and is connected by means of a lateral opening 94 and a channel 95 withthe adjusting cylinder chamber Into this bore @3 the other, also openand enlarged end 97 of sleeve 85 protrudes, being sealingly guided inbore 93 in a hollow piston.

The casing of an operating oil pump, which is generally designated byreference numeral 99, is screwed to the bearing plate 2 by means ofscrews 98. This casing comprises two casing parts 1&1 and 102 which areheld together by the screws 98. As is well known, the operating oil pumpserves the purpose of feeding oil under pressure to the hydraulic systemof the transmission so that the transmission can operate. With thetransmission according to the invention, the operating oil pump need notdevelop particularly high pressures and any desired type of pump may beused. With the described illustrative embodiment, a known type ofcycloidal pump is provided as operating oil pump 99, as can be seen inFIG. 6. Therein, an outer pump body 103 provided with a kind of roundedinternal toothing, (FIGS. 1 and 6) is supported in the casing part 15.1,inwhich an inner pump body 164 with a similarly rounded externaltoothing rolls. The inner pump body 1134- is keyed with shaft 6 at 1%.With the turning of body 104, oil is supplied in known manner from asuction chamber (FIG. 6) of the casing part 1191 to the pressure chamber157. With the design, body 103 in the casing part 101 rotates with V ofthe speed of driving shaft 6 (7 teeth outside, 6 teeth inside).

The suction chamber 166 is connected with a sump 110 through a channel108 (FIGS. 1 and 6). The pressure chamber 107 is connected through achannel and pipe 169 with an annular chamber 24 around the shaft 12 inthe stationary cylinder block 25 (FIGS. 1, 6 and 8).

The cylinder block 25 has axial regularly spaced cylinder bores 112, inwhich the postons 27 reciprocate. II1- side connection bores 113connected with these cylinder bores, have a smaller diameter and openthrough double holes 121 to face 26 of operating slide valve 17. As canbe seen in FIG. 8, the lowermost connecting bores 113 of two adjacentcylinder bores 112 are offset in opposite directions to provide a spacethrough which the operating oil channel 109 passes. In a similar manner,two connection bores 113 are eccentrically offset in opposite directionsrelative to their cylinder bores 112 so that between them a space isprovided for the passage of an adjusting crank 114 which engages into anannular groove 116 of sleeve 22 with a pin 115. Through rotation ofcrank 114 sleeve 22 and consequently the tubular control slide 86 can beaxially displaced relative to shaft 12 during operation of thetransmission.

The annular chamber 24 is in connection with an annular chamber 23 ofthe operating slide valve 17. Chamber 23 is connected with thearc-shaped control chambers 119, 121, 119', 121, (FIG. 7) of theoperating slide valve 17 through a slot 111 and through two check Valves117, 118. Thus, operating oil always flows into the control chambersacting as suction chambers if the oil pressure therein drops below theoperating oil pressure. Opposite control chambers 119 and 119 or 121 and121, respectively, of the operating slide valve 17 are connected witheach other through channels 122 (FIGS. 1 and 7). In the illustratedembodiment, these channels extend obliquely since the control chambers119, 121 of the operating slide valve have a larger diameter than thechambers 119', 121'. The operating slide valve 17 has a radial bore 123in the space between the arc-shaped control chambers 119, 121 oppositeeach other, which bore is closed by a plug 124 (or a safety valve). Theinner end of bore 123 is open at the groove 19. Through a slide valve125 and a transverse bore 126 bore 123 is always connected with thatcontrol chamber 119, or 121 depending upon which is under the higherpressure. With the transmission in question, this may be depending onthe position of the oblique disk 62 (FIG. 7) either the left or theright chamber 119 or 121 of the controlling slide valve 17. Slide valve125 is resiliently suspended on both sides by springs 127 which aresupported at plugs 128 which are screwed into bore 126 and close thelatter. Collars 129 of the plugs 128 on the one hand serve as guide forthe springs 127 and at the same time as stops for slide piston 125.

The tubular control slide 86 is sealingly guided n the hole 21 of theoperating slide valve 17 and has holes 131 (FIG. 1) in its walls withinthe range of bore 123.

The described arrangement operates as follows:

Through the adjusting crank 114- and sleeve 22, the tubular controlslide 86 may be axially displaced in groove 19. In the left extremeposition of the slide, the end 97 is located in the dead zone of bore 93beyond the control opening 94. At this setting, oil may flow from theadjusting cylinder chamber 96 through channel 95, opening 94-, bore 93about the outside of slide 86 and then into the sump 110. The oil in thecylinder chamber 96 is under pressure due to the force exerted bypistons 61 against the disk 62. With adjusting piston 72 and obliquedisk 62 in the positions shown in FIG. 1, the pistons 61 are moved intothe cylinders 59 as far as possible. With a retraction of piston 72, dueto the escape of oil as described, the oblique disk 62 pivots orinclines about the projecting shoulder 69, whereby the pistons 61 arepermitted to move out of their cylinders a greater or less extentdepending upon the angular position of disk 62. The pistons 61continuously exert a force on the oblique disk, which force is opposedto the force of the adjusting piston 72 and urges the oblique disk 62toward the left. When the piston 72 is fully retracted, the inclinationof the oblique disk is 15, having executed a pivoting movement about theoff-center shoulder 69. Thus, under the influence of the force exertedby the pistons 61, the oblique disk 62 follows the adjusting piston 72on drainage of the oil and thereby moves in the guide surface 71 fromvertical position to an inclination of 15.

The right end of the control slide 86 in the left extreme position ofthe same is positioned before the control opening 89. Now, operating oilflows from the high pressure chamber of the transmission through channel126, bore 123, holes 131 into the tubular control slide 86, out of theright end thereof into the opening 89 and through channel 91 into theadjusting cylinder chamber 92. Thus the piston 43 executes a strokecontinuing to move out until the control opening 89 is closed by theenlarged end 88 of the control slide 86. This movement of the pistoncauses the oblique disk 28 to move to a vertical position from the fullyinclined position. It pivots at the projecting shoulder 35 and slides inthe guide surface 42. In the manner described in connection with thepump system of the transmission, a resetting force of the pistons 27tends to counteract the force and movement of adjusting piston 43.

If, now, the control slide 86 is slowly moved to the right, initiallynothing changes in the pump section at the left end of the slide. Theenlarged end of slide 86 slides in the dead zone of bore 93 beyond thecontrol opening 94 just as before. The oblique disk 62 remains in itsposition of maximum inclination. However, in the motor system at theright end of the transmission, the control opening 89 is uncovered.Thereupon oil flows from chamber 92 through channel 91, opening 89,passes behind the enlarged end 88 through bore 87 along the outside ofslide 86 into the sump 110. Thus the piston 43 retracts until theopening 89 is again closed by the enlarged end 88. Thus piston 43 firstfollows the movement of the control slide 86, whereas piston 72 is notinfluenced by the initial movement thereof.

Under the influence of the resetting forces of the pistons 27, theoblique disk follows the adjusting piston and assumes an inclinedposition.

On further displacement of the control slide 86 to the right, theenlarged end 97 travels beyond the control opening 94. Now operating oilflows through tubular control slide $6, opening 94 and channel 95 intothe cylinder chamber 96 so that the piston 72 starts its stroke untilthe control opening 94 is closed again. The right end of the controlslide 86 moves in the dead zone of bore 87 so that the adjustingmovement does not exercise an influence any more on piston 43. Incontrast thereto, piston 72 now follows the adjusting movement of slide86. The oblique disk 62 is moved into its described vertical positionand on further movement of the control slide 86 even somewhat beyondthis position, (as is indicated in FIG. 5). With an opposite movement ofthe control slide 86, the correspondingly reverse operation takes place.

It must be observed that the control slide 86 with each of the pistons43 and 72 provides a follow piston system with dead stroke, the pick-uppiston of which is provided by the control slide which simultaneouslycarries the pressure means. Such an alternating action of the controlslide 86 on the piston 43 or on the piston 72 can in this manner, ofcourse, only be realized with a unilaterally acting adjusting piston.Therefore a suitable resetting force had to be provided which theworking pistons 27, 61 are supplying.

The cylinder block 58 is driven at the input speed in of the shaft 6.The oblique disks 28 and 62 are conll nected to the driven shaft. In theextreme left position of the control slide 86, the oblique disks 62, 28are in the position as is schematically indicated in FIG. 2. The rightsystem operating as motor is in its zero position and is not in aposition to receive any oil. The

system at the left end of the transmission, operating as pump, is atmaximum capacity. In this position driving shaft 6 and driven shaft 12are rigidly coupled with each other through the working oil. The obliquedisks and consequently the driven shaft are rotating with the inputspeed and there is no flow of working oil. Consequently, an i=1z1transmission ratio (direct gear) and a purely mechanical powertransmission are obtained.

In the position of the oblique disks according to FIG. 4, the leftsystem does not pump any oil. The rotation of the driving shaft has noinfluence whatsoever on the oblique disks and on the driven shaft.Consequently i=oozl and the engine is idling.

Between these two extremes, as indicated, for example, in FIG. 3, liethe various reductions. In the position according to FIG. the pressureand the suction sides at the operating slide valves are exchanged andconsequntly the driven shaft runs in opposite direction (reverse gear).

Quantitatively the following applies:

If v is the volume of working oil capable of being pumped with a givensetting of the oblique disk 62 per relative revolution of the cylinderblock 58 and the oblique disk 62, and v the volume which is received perrevolution by the motor system 25, 28, then v (adjustment of piston 43and oblique disk 28) the transmission ratio 1' may be adjusted from Afurther increase of v (secondary adjustment) would result inconstructional difiiculties. Therefore, the oblique disk 62 is nowadjusted in the described manner and consequently v continuouslydecreased, whereby high reductions up to idling may be adjusted (primaryadjustment).

FIGS. 9 and 10 show a corresponding design for a transmission withoutpower branching (where the input power may be purely 'mechanicallytransmitted to the driven shaft).

Reference numeral 135 designates a transmission casing wherein on oneside the driving shaft 137 is supported in a bearing 136 and on theother side the driven shaft 139 in a bearing 138. On the driving shaft137 an operating oil pump 141 is mounted which corresponds to the pumpas shown in FIG. 6. The operating oil pump 141 draws in oil over asuction pipe 140. from a sump 143 and feeds the oil into an operatingoil pipe 144.

The casing 135 is subdivided approximately in the middle by an operatingslide valve 145 which is fixed to the casing by screws 1%. 'A centralshaft 147 is nonrotatably mounted in the operating slide valve 145. Thisshaft on the left side abuts the slide valve 5.45 with a shoulder M8and'has a longitudinal groove 149 (FIG. 10) into which a spline of theslide valve 145 protrudes so that the shaft 147 is non-rotatabiypositioned in the operating slide valve. On the ends of shaft 147 arepositioned (FIG. 2)

through adjusting cylinder bodies 151 and 152, respectively (withadjusting pistons), and oblique disks or swash plate assemblies 153 and154, respectively. These are of the same design as the correspondingparts of FIG. 1 and are therefore not described here in detail. Cylinderblocks 155, 156 abut the operating slide valve 145 on both sides and thepistons engage the oblique disks 153 and 154. These cylinder blocks aredesigned in substantially the same manner as are the cylinder blocks 25and 58 of FIG. 1. Since, however, both cylinder blocks are rotatinghere, no provision is made in the cylinder block 156 for the extensiontherethrough of operating oil channel or adjusting means. In contrast tothe embodiment according to FIG. 1, the operating slide valve 145 isstationary here. The cylinder blocks 155, 156 are coupled with thedriving and the driven shaft 137, respectively, through bellshapedcoupling parts 157 and 158, respectively. These enclose the controlcylinders 151, 152 and the oblique disks 153, 154 mounted on the shaft147 and are provided with internal toothings 159, 16%) which are inclearance engagement with corresponding external toothings of thecylinder blocks 155, 156 and permit fitting of the cylinder blocks 155,156 relatively to the faces of the operating slide valve Adjustment ofthe oblique disks 153, 154 takes place in a manner similar to thatdescribed with reference to the embodiment according to FIG. 1 by meansof control slides which are movable in groove 149 of shaft 147. However,two tubular control slides 161, 162 are provided here which areindividually and independently movable, slide 151 controlling theoblique disk 153 and slide 162 the oblique disk 154. The control slides161 and 162 are in communication with the chamber of the operating slidevalve 145 that serves as a high pressure working oil chamber, through aradial channel 163 and a T-channel i165 containing a slide valve 164(FIGURE 10). In this respect the design is completely analogous to thataccording to FIGS. 1 and 7. In a completely analogous manner the supplyof the operating oil takes place. Only, the operating oil is notsupplied over the detour of the cylinder block as it was necessary withthe design according to FIGS. 1, 7 and 8, but the operating oil pipe 144is directly connected with a radial channel 166 of the stationaryoperating slide valve. This channel is in communication with the controlchambers of the operating slide valve through check valves 167, 168(FIG. 10).

The adjustment of the tubular slides 161 and 162 herein is also effectedacross the stationary operating slide valve 145. One slide is adjustedby means of a hollow shaft 169 (FIG. 10) to which a handle 171 isafiixed at its external end and an external toothing 172 provided at theinternal end. The toothing 172 is in engagement with a toothed rack 173(FIGS. 9 and 10) which engages a stop T74 of slide 162. A second shaft175 with a handle 1'76 and a toothed gear 177 extends through the hollowshaft 169. Gear 177 is in engagement with a second rack 178 parallel andarranged to reciprocate alongside to the first. Rack 17% engages a stop179 of the control slide 161. The racks 173 and 178 are axially movablyguided in a recess of the stationary shaft 347 and the shafts 169, 175extend through a transverse bore in shaft 147, as can be seen in FIG.10. By rotation of the handles I71, 176, the racks 173, 178 may beindividually axially moved and therewith the control slides 161, 162.This permits an adjustment of the oblique disks 153 and i554independently of each other.

With the transmission of FIGS. 9 and 10 no power branching takes place.System 153, 155 acts as a pump which is being driven by the shaft 137.The system 154, 1553 acts as an oil motor which drives the shaft 139 andis supplied with working oil by the pump 153, 155. Thereby thetransmission ratio is center bearing boxes 206 (FIG. 15). side of thecentral axis of the transmission, the adjusting Reverting to theembodiment of FIG. 1, instead of across the stationary parts, i.e.,cylinder block (FIG. 1) or operating slide valve (FIG. 9), thedisplacement of the control slide 86 may also be effected centrallythrough the driven shaft 12, as is indicated in FIG. 11 as amodification of FIG. 1. An adjusting rod 179 extending axially into theshaft engages the control slide 86 by means of a pin 181 protrudingthrough a longitudinal slot 180 of shaft 12. The adjusting rod protrudesat the driven end of shaft 12 and has a ring defining a recess 182 intowhich an adjusting handle 183 is fitted.

Turning now to the embodiment of FIGS. 12-17, reference numeral 184designates a core shaft extending through the hydrostatic transmissionat its axis. On this shaft 184 at the left end of the transmission, asleeve 185 having radial bores 186 is supported. The bores 186 open tothe right, that is to say inwardly to the transmission, into an annularchamber 187 which surrounds the core shaft 184 and is defined by a ring188 which is inserted into the sleeve 185. To the left, that is to sayoutwardly, a labyrinth packing 189 is provided. A hollow driven shaft190 surrounds shaft 184 almost for the total length thereof, a smallspacing between the two shafts providing an annular channel space aroundshaft 184, which space is in communication with the bores 185 throughthe annular chamber 187. As will be explained hereinafter, this annularchannel 191 serves the central operating oil supply. The operating oilis supplied by a pump 216 to be described hereinafter and forcedinwardly into the annular channel 191 through the bores 186, and can betapped in a manner to be described hereinafter at suitable points.

An adjusting cylinder 192 is keyed with the driven shaft 190. Thiscylinder is secured by rings 193, 194 against axial displacement. Anadjusting piston 195 is disposed within in the cylinder and is axiallymovably guided on the driven shaft 190. The piston 195 has a collar 196with an axial external groove 197 (see also FIG. 15). The collar 196tightly encloses and rotates with the driven shaft 190. On the collar196 a toroidal ring 198 with spherical surface is axially movablyguided. On the toroidal ring 198 an oblique disk 199 withcorrespondingly spherical inner surface is supported. This oblique disk199 comprises ahub portion 290 of cylindrical basic shape with saidspherical inner surface, a base ring 291, which is supported on a radialflange 202 of the hub portion 200 and a race 203 which is supported onthe base ring 201 by a thrust bearing 204 with three sets of rollers.The whole is held together by a shell 205 with flanged edges.

1 The hub portion 200 has axial grooves opposite each other of the widthof the toroidal ring 198. These make it possible for the toroidal ring198 to be moved with its center plane perpendicular relatively to thatof the hub portion 288 into the same until the centers of the sphericalsurface, and inner surface respectively, coincide. Then, parts 198, 208may be rotated in opposition to each other as desired and ring 198 issecured in the portion 200.

The adjusting cylinder 192 has two co-axial but off- On the oppositepiston 195 has two co-axial bearing boxes 207. The axes of the bearingboxes 296 and 207 are parallel relatively to each other. Twosemi-cylindrical bolts 208 and 209, respectively, are supported in thebearing boxes 206 and 207. The shape of these bolts may best berecognized in FIG. 15. They show central recesses which are provided toaccommodate the collar 196. The bolt 208 engages into the groove 197 ofcollar 196 with a spline 210. The oblique disk 199 is supported on theplane surfaces of the bolts 208 and 209.

The oblique disk non-positively abuts the bolts 2118 and 299 in a mannerto be described hereinafter. With movement of the adjusting piston 195the bolt 208 is unmoved while the bolt 289 moves with the movement ofthe adjusting piston 195. Thus, the oblique disk 199 is inclinationallymoved in counter-clockwise direction in FIG. 12 with outward stroke ofthe piston, the bolts 208 and 299 rotating accordingly in their hearingboxes 206, 207 so that they constantly abut the oblique disk 199 withtheir plane surfaces. Thus, the oblique disk 199 inclines about itscenter of gravity which remains on the rotational axis of thetransmission. This inclinational movement is super-imposed by an axialtranslation movement. This is taken into account in that the toroidalring 198 is movable in axial direction on sleeve 196.

The shaft 184 is supported in the hollow driving shaft 212 by means ofthe sleeve and the adjusting cylinder 192 and a needle bearing 211, saiddriving shaft being supported in a casing 214 by means of a ball bearing213. The driving shaft 212 provides an eccentric 215 for the pump 216which will be described hereinafter. Then, the driving shaft 212provides a bell-shaped casing 217 which encloses the adjusting cylinder192 and the oblique disk 199 and by means of a toothing 2181 engages agear rim 219 on the periphery of a cylinder block 220. In the cylinderblock 228 a ring of spaced axial pistons 222 are guided in cylinders 223around the driven shaft on which the cylinder block 220 is rotatablysupported by means of a needle bearing 221, the pistons engaging theoblique disk 199. The cylinders 223 are in connection with the face 225of an operating slide valve 226 through axial channels 224, said valverotating with the driven shaft 190, the cylinder block abutting the faceof the valve.

The pump 216 is a cycloidal pump. 0n the eccentric 215 a secondeccentric 227 is supported. Both eccentrics 215 and 227 provide aneccentric guide path with easily variable eccentricity. On the eccentric227 a cycloidal ring 228 with an external toothing is supported which inthe known manner rolls within a stationary internally toothed cycloidalring 229, this stationary ring having one tooth more than the rotatingring with external toothing. The two eccentrics allow for a. minorvariation of the eccentricity, making possible the alignment of theinner ring 228 relatively to the outer ring 229. The eccentric 227 hascontrolling slide valve 230 with radial bores 231 and the inner ring 228as well as the eccentric 215 are provided with radial bores 232 and 233.

For the purposes of description of the present invention it will besufficient to know that the pump 216 sucks in oil from the sump throughconnection 234 and chamber 235 through not distinguishable lateralopenings of the eccentric 227 and feeds it inwardly where it flows intothe annular channel 191 through channels 186.

FIGURES 16 and 17 show the further distribution of the operating oil. inthe operating slide valve 226 the oil flows from the annular channel 191through radial channels 236 and 237 and check valves 238 and 239,respectively, to the suction side and the pressure side, respectively,of the controlling slide valve. Through a further radial channel 242 oilis furthermore fed from the annular channel 191 to a pressure-regulatingvalve 243. The pressure-regulating valve has a piston 244 controlling anoutlet channel 245. The operating oil pressure in the system acts on thepiston 244 on the one side, a spring 246 being arranged on the otherside in a chamber 247 which normally is in communication with the outletthrough channels 249' and 249 (FIG. 17). The piston 244 is designed as adifferential piston and with a central portion 248 is sealingly guidedin chamber 247. The pressure in chamber 247 therefore only acts on oneannular surface around the central extended portion 248 while theatmospheric pressure does act on the front surface of portion 248. Aslong as chamber 247 is under atmospheric pressure, the design of thepiston as a differential piston has no particular effect. The pressureis adjusted in the system so that the force acting on the entire frontsurface 244' of the piston 244, just counterbalances the spring tension.If the pressure increases, the piston further opens the channel 245,and, if the pressure is reduced, the outlet is more considerablythrottled.

pistons.

In FIG. 17 it is shown that in a transverse bore 250 which at one end isin communication with the pressure side of the operating slide valve andon the other in communication with the suction side of the operatingslide valve, a slide piston 251 is arranged to slide between two stops252 and 253. Between these stops 252 and 253, channel 25% is traversedby a channel 254. If the operating slide valve carries the workingpressure on the right side in PEG. 17 and suction on the left, thenpiston 251 is moved to the left side position as illustrated, by theworking pressure so that channel 254 is connected with the right side ofthe operating slide valve that carries the Working oil pressure. If thesides of the controlling slide valve exchange their function-Which ispossible-and the pressure side is on the left and the suction side onthe right, then the piston 251 is moved to the right by the pressure sothat the left side of the operating slide valve and of channel 250 isconnected with channel 254. Channel 254 therefore in any event carriesthe working pressure. Channel 254 opens into a longitudinal channel 255wherein a tubular control slide 256 for controlling the oblique disks ismovable and through which the pressure oil is fed into the adjustingcylinder.

The working pressure is also effective in channel 254 below a piston257. This piston 257 is designed as a differential piston. The operatingoil pressure acts on a greater area 258, While an annular area 259resulting from the step is exposed to atmospheric pressure. The pistoncontrols channel 249. In the illustrated upper end position, channel249' is in communication with the atmosphere through the annular chamber260 and channel 249". This is the normal condition, where a high Workingpressure is existing and the piston 257 is therefore pressed upwardly bythe working pressure against the action of the operating oil pressure.The regulating valve 243 adjusts a relatively low operating oilpressure. This operating oil pressure exists on the suction side of theoperating slide valve, whereas the working pressure is raised above theoperating oil pressure in accordance with the transmitted torque. Theoperating oil pressure counteracts the Working pressure with respect tothe development of the torque. If, now, the working pressure decreasesbelow a certain minimum value due to a decrease of the transmittedtorque, then the operating oil pressure, since it acts'on a greater area258 of piston 257, can overcome the working pressure and move the piston257 into its lower end position (FIG. 17). In tlus position of thepiston 257, chamber 247 is connected with the operating oil pressurethrough channel 249'. Then, the operating oil pressure also acts on theannular surface of piston 244 around the center portion 248. The forceexerted on this area in the direction of the spring tension thereforecompensates the force which is exerted in opposition to the springtension on the corresponding surface portion of surface 244. The activesurface for the force exerted by the operating oil pressure andcounteracting the spring 246 therefore only still corresponds to thefront surface of the piston center portion 24-8. Therefore, acorrespondingly higher pressure must be adjusted so that the forcecaused by the operating oil pressure counterbalances the spring tension,since the operating oil pressure acts on a smaller area. Thus, theoperating oil pressure increases. In the same degree, the

a working pressure increases, since, for example, with a erating oilpressure is determined by the transmitted torque and remains constant aslong as the torque does not change. The increase of the operating oilpressure and consequently of the working pressure results in the factthat also with minor transmitted torques a sufiicient pressure ismaintained in the system and a satisfactory non-positive connection isguaranteed always to the axial In particular, it assumed that because ofthe iii force exerted by the pistons, the oblique disk cannot straightenout under the influence of centrifugal force.

If the transmitted torque increases again, then the working pressurecorrespondingly rises above the operating oil pressure. Then a momentoccurs where the working pres sure again overcomes the operating oilpressure at the piston 257. At that moment chamber 247 is againconnected with the outlet. he regulating valve 243 again adjusts thenormal low operating oil pressure and working pressure and operating oilpressure together decrease accordingly.

A pressure chamber 261 (FIG. 15) is defined by grooves on the face 225of slide valve 226. Within the pressure chamber 261 a pressure reducingpiston 262 is arranged with which a high-pressure piston 263 abuts,piston 263 being in connection with the high-pressure' or workingpressure-chamber on the other side through a connection 264. Piston 263presses the pressure-reducing piston 262 to the left whereby the latteropens a connection of the pressure chamber 261 and of chamber 267 withthe operating oil chamber through connection 266 through controlopenings 265. If the pressure in the pressure chamber 261, which acts onthe large area of piston 262, overcomes the high pressure which onlyacts on the small area of the high-pressure piston 263, then connection266 is throttled and an outlet 268 of the pressure chamber 267 isreleased. Thus, the pressure chamber 261 is subject to a pressure whichis always proportional to the working or high pressure of connection264, but substantially lower than the latter.

The pressure chamber 261 exerts a force on the cylinder block 229, whichcounteracts the centrifugal force momentum and consequentlyhydraulically receives the bearing pressure occurring through the loadof the centrifugal forces.

FIG. 18 presents a modification of the embodiment in FIGS. 12 to 15.Herein the collar 271 of the adjusting piston is provided with aspherical torus 272 which is integral or ailixed to collar 271. On thistorus 272 the oblique disk 273 is supported with a cylindrical innersurface. This support permits at the same time an inclinational movementof the oblique disk 273 and an axial movement, the latter being effectedthrough displacement of the cylinder 274 on the torus 272. With thisdesign the center of gravity of the oblique disk may travel on curve275. It can be seen that here, too, the center of gravity alwayspractically remains on the rotational axis of the transmission.

The design according to the invention as described with reference toFIGS. 12-18 is, of course, not limited to power-branched transmissionsof the type herein described, but is also applicable to transmissionswhich are not power-branched.

In the transmission of FIG. 12, the cylinder block 220 is driven by thedriving shaft. The shaft 184 with the sleeve 185 and hollow driven shaft198 and the oblique disk 199 with the adjusting gear 15 2, as well asthe controlling slide valve part 226 rotate with the output speed. Thesame applies for the oblique disk with adjusting gear connected to theoutput or motor side (not shown), while the cylinder block connected tothe output side is stationarily arranged with respect to the casing.Thus, a power-branched transmission is dealt With here being of the samebasic design as is provided with the 7 transmission according to FIG. 1.

FIG. 19 presents another form of power-branched transmission. Referencenumeral 301 designates a hollow driving shaft which has a bell-shapedextension and provides a hollow cylinder 3. 52 which surrounds theoblique disk system 363 and which drives the cylinder block 305 withtoothing 364.

The hollow driven shaft 3% encloses a core shaft 307 which extendsthrough the whole transmission, the hollow shaft surrounding the coreshaft with a small spacing therefrom to form an annular channel 33)extending along the length of shaft 3%. The oblique disk system or swashplate assembly 3% is connected with the driving shaft. An operatingslide valve 331% and the oblique disk system or swash plate assembly 311is connected with the driven shaft 313%. The cylinder block 312,associated with the output of the transmission, is stationarily arrangedin the casing 314 by means of a hollow cylinder 313. The operation ofthis transmission substantially corresponds to that of the transmissionaccording to FIG. 1.

Shaft 393 is supported with the oblique disk system in the bell-shapedextension of the driving shaft Sill by means of a needle bearing 315.Shaft Slit on its part supported in casing 314 by means of a ballbearing On the other side, shaft 398 with the oblique disk system 311 issupported in casing 314 by means of a ball hearing 317.

An operating oil pump 31% is arranged on the driving shaft 301, which isdesigned as novel cycloidal pump, as illustrated in FIG. 20. The drivingshaft Frill turns in a ring 319 having an annular extension 3% andradial bores 321. Bore s 321; are inwardly connected with annularchannel sue, while the ring 319 provides for a sealing of channel 3&9and bores 321 through a labyrinth packing. The driving shaft Sillprovides an eccentric (FIG. 20). On the eccentric 323 an eccentric hoop324 is arranged the periphery of which is eccentricslly arrangedrelatively to that of the eccentric 323. From this double eccentric 323,324, however, a resulting eccentricity follows relative to the axis ofshaft sat. On the eccentric hoop 324 a gear 325 is supported which withsuitably curve-shaped teeth rolls in a corresponding internal toothing326 of a ring 327 which is stationary with respect to the casing andcentric relatively to the shaft Sill. Thereby the chambers between theteeth of gear 3-25 and rii 327 are successively enlarged and diminishedagain, if the eccentric 323 and the eccentric hoop 324 are rotated withthe driving shaft 361. Go the one side the teeth re engaging relativelyto each other and on the opposite side they are crest to crest. Tneinternal teething 326 has one tooth more than the gear Gear 325 hasradial bores between all teeth. These open into an operating slide Valve329 at the periphery of the eccentric hoop 324. The shell of this hoop32 5 has two halfmoon shaped recesses 3353, one of which can be seen inFIG. provides the pressure side of the operating slide valve 32). Thisis connected through radial bores 331 with a half-moon shaped recess33-2 of the eccentric 323. Channels 333 of the eccentric 323 open intothe annular chamber 3%. The recess connected to the suction side of theeccentric hoop is connection with an annular chamber 335 (FIG. 19)through axial bores 334, from where a pipe 33% leads into the sump.

The pump sucks in oil from the sump and feeds it inwardly through theopenings 328, 331, 321 into channel From there it is fed through radialbores 3337 in the usual manner through check valves 338 into the systemof the axial pistons. The pressure of the operating oil is kept constantby means of a pressure-regulating valve 339 (FIG. 21). Thispressure-regulating valve has a piston 34-9 sliding in a bore 341. Aspring 342 acts on the piston 34% on one side, the operating oilpressure on the other side. Piston 34%) controls an outlet channel 343,344 (FIG. 22). The outlet channel is throttled in the usual manner sothat the operating oil pressure is just counterbalanced by the springtension.

The oil flowing off through outlet 343, 344 of the pressure-regulatingvalve 339 travels into an axial channel 345. the annular chamber 346 andan axial groove 347 in shaft 3%. Simultaneously it is fed through agroove 348 of the operating slide valve 314) into a groove 349 of shaft3%, providing an extension of grooves 347, but being separatedtherefrom. The oil flows off axially in the grooves and is then sprayed,as illustrated, against the lid oblique disks 303, 311 under theinfluence of centrifugal force, said disks being cooled thereby.

The oil centrifuged from the oblique disk 393 is thrown against theinside wall of cylinder 3% which is covered with a pilot-cloth(Molton-cloth) 359. The cloth 350 is kept in place by a wire net 351.The dirt particles contained in the oil are caught in the cloth so thata continuous cleaning of the oil is being effected and with low oilconsumption the life of the transmission is substantially prolonged. Theoil flows through opening 352 back into the sump through tray 353 and iscooled during this passage. The pilot-cloth may easily be changed fromtime to time. i

A tubular control slide 354 slides in the grooves 347, 349 of the shaft3%. This slide serves for adjusting the oblique disks in manner as abovedescribed. The control slide 354 is connected with an adjusting ring 355which is axially movably arranged exteriorly on the driven shaft and maybe axially displaced to adjust slide 354 by means of an annular groove356 through adequate means engaging therein.

lnvention is claimed as follows:

' 1. In a hydraulic axial piston machine including shaft means at leasta portion of which is rotational and defines a rotational axis, acylinder block device having a plurality of pistons mounted in cylinderstherein, positioned about said axis and movable parallel to said axis,and a swash plate device, with one of said devices being connected tosaid rotational portion of said shaft means for rotation therewith, theimprovement comprising: said swash plate device being positioned aboutsaid axis and pivotal with respect to said rotational axis about apivotal axis transverse to the rotational axis and spaced to one side ofthe rotational axis, said swash plate device having a pressure meansoperatively engaging said pistons whereby the pistons urge the swashplate device in one direction of movement about said pivotal axis;inclination adjusting means including a single acting fluid operatedlinear motor means having a movable part operatively engaging the swashplate device and movable parallel to the rotational axis to urge theswash plate device in the opposite of said one direction about saidpivotal axis when fluid under pressure is supplied to said motor means;and fluid control means connected to said motor means to adjustablyposition the position of the movable part and thereby set the positionof the swash plate device about said pivotal axis and thus theinclination of the pressure means with respect to the rotational axis.

2. In a machine as set forth in claim 1, wherein said swash plate devicehas a convex cylindrical guide surface on the side thereof opposite saidpressure means, and said movable part has a mating concave cylindricalguide surface abutting the guide surface of the swash plate device.

3. In a machine as set forth in claim, 1, wherein said motor meansincludes an adjusting cylinder member and an adjusting piston membertherein, one of said members being movable parallel to said rotationalaxis and being said movable part; said control means includes a hollowslide movable parallel to the rotational axis to control the flow offluid for the adjusting cylinder, and means operatively connected tosaid side and externally operable to adjust the axial position of theside and thus the flow of fluid for the adjusting cylinder.

4. In a machine as set forth in claim 3,. wherein said movable partincludes a closed bore defining a control cylinder aligned with theslide, and also includes a passageway communicating with said bore at apoint spaced from the closed end thereof and communicating with theadjusting cylinder, and said slide includes an enlarged head on the endadjacent said bore, said head being of a size to serve as a piston insaid control cylinder and of an axial length to close the bore end ofthe passageway.

5. In a machine as set forth in claim 4 and including a pump to supplyhigh pressure operating oil, and wherein Iii-i said control means isadapted to supply the high pressure operating oil to the slide.

6. In a machine as set forth in claim 1 and including a central guidemember coaxial with said rotational axis. and wherein said motor meansincludes a fixed adjusting cylinder concentric with said rotational axisand an adjusting piston movable therein, said adjusting piston beingsaid movable part; said swash plate device is supported on the centralguide member for inclinable and axial movement with respect thereto; andsaid inclination adjusting means includes two supporting members,parallel to each other, transverse to the rotational axis and atopposite sides of the guide member respectively, one of said supportingmembers being mounted on the adjusting cylinder and the other of theadjusting members being mounted on the adjusting piston.

7. In a machine as set forth in claim 6, wherein said supporting membersare semicylindrical bolts having a plane surface, said supportingmembers being rotatably mounted in the cylinder and piston respectivelywith the plane surfaces facing and abutting the swash plate device.

8. In a machine as set forth in claim 6, wherein said guide member has atoroidal ring mounted thereon for axial movement along said rotationalaxis, said ring having a semi-spherical external surface, said swashplate means having an inner semispherical surface about and in contactwith the surface of the ring.

9. In a machine as set forth in claim 6, wherein said guide member has atoroidal ring mounted thereon for axial movement along said rotationalaxis, said ring having a semi-spherical external surface, said swashplate means having an inner semicylindrical surface about and in contactwith the surface of the ring.

10. In a machine as set forth in claim 6, including a chambercommunicating with one group of the cylinders of the cylinder blockdevice and the working pressure in said chamber is a function of theforce being transmitted between the devices; and including a pump tosupply high pressure operating oil to the cylinders of the cylinderblock device, regulating means communicating with the pumpdischarge tocontrol the operating oil pressure, said regulating means beingoperatively connected to said chamber to increase the operating oilpressure in response to a decrease in working oil pressure and todecrease the operating oil pressure in response to an increase inworking oil pressure.

11. In a machine as set forth in claim 10, wherein the regulating meanscomprises a resiliently suspended todiiferential regulating piston whichon one side is subject to the pump pressure and is opposed by a springand controls the outlet for the operating oil, and with a decrease ofthe working pressure operating oil pressure is applied to bear on thespring side on an area less than that of the one side so as tocounter-balance a portion only of the force applied to said one side.

12. In a machine as set forth in claim 11, and including a reversingmeans with a differential reversing piston movable between two extremepositions and acted on in one direction by the working pressure andacted upon in the other direction and over a larger area by theoperating oil pressure, said reversing means being connected to theregulating means and to an outlet to provide a connection through whichthe spring side of the regulating piston is fully exposed to the outletpressure Where in the normal operation of the machine the workingpressure overcomes the operating oil pressure and maintains thereversing piston in one extreme position, and to supply the operatingoil pressure past the reversing piston to said area on the spring sideof the regulating piston when the working pressure decreases and thereversing piston moves into the other extreme position.

13. In a machine as set forth in claim 1, wherein said cylinder blockdevice has a plane face positioned normal to the rotational axis and atthe opposite side thereof from said cylinders, and ports in said facecommunicating with said cylinders; and including a slide valve platehaving a plane face abutting said plane face of the cylinder blockdevice and having ports therein for fluid communication with saidcylinders, said face of said slide valve plate having a pressure chamberin said face larger than the ports in the cylinder block device, whichchamher is subject to a pressure proportional to the working pressureand constitutes a momentum with the residual force of the axial reliefcounteracting the centrifugal force momentum of the pistons.

14. In a machine as set forth in claim 1, wherein said shaft meansincludes a core shaft and a hollow shaft surrounding the core shaft witha space between the two shafts, said machine including an operating oilpump delivering oil under pressure to said space, and a slide valvesurrounding said shafts and communicating with said space to receive oiltherefrom.

115. L1 a machine as set forth in claim 14, wherein said hollow shaft isthe driven shaft and one of said devices is connected thereto, said pumpsurrounds said core shaft, and said shaft means includes a driving shaftconnected to said pump to operate the same and to the other device torotate the same.

16. In a machine as set forth in claim 1, and including: a pump tosupply with pressure operating oil; an oil line communicating betweensaid pump and the cylinders of the cylinder block device; and meansconnected to said line to regulate the pressure at which the oil issupplied to the cylinders, said regulating means including a pressurerelief valve and a relief discharge passage extending therefrom with aportion being in an axial channel in the shaft means, said passagehaving an outlet adjacent said swash plate device to spray thedischarged oil by centrifugal force over the swash plate device.

17. In a machine as set forth in claim 16, and including a hollowcylinder about the swash plate means, said cylinder having an innersurface covered with a cloth to catch and hold foreign particles in theoil.

18. In a machine as set forth in claim 3, wherein said shaft meansincludes a rotatable shaft with a longitudinal opening therein and agroove extending longitudinally along the side thereof, said slide beingpositioned in said groove, said means to adjacent the position of theslide including an adjusting ring coaxial with the shaft at one end ofthe machine and movable axially with respect to the shaft, and means inthe longitudinal opening in the shaft and connecting the ring and slide,whereby the slide may be moved by moving the ring.

19. In a machine as set forth in claim 3, wherein said shaft meansincludes a shaft with a groove extending longitudinally along a sidethereof, said machine including a stationary part about said shaft, saidslide being positioned in said groove, said means to adjust the positionof the slide including shaft means extending through said stationarypart and rotatable with respect thereto, and means operativelyconnecting the inner end of the shaft with said slide.

20. In a machine as set forth in claim '19, wherein said cylinder blockdevice is the stationary part and the shaft of the shaft means is arotatable shaft.

21. In a machine as set forth in claim 19, wherein said stationary partis a slide valve plate said shaft of the shaft means is a fixed shaftmounted on said plate.

22. A power transmission comprising in combination: a frame; rotatableshaft means defining a rotational axis and including a driving shaft anda driven shaft; a slide a plate valve device positioned about said shaftand hav ing two contact faces normal to said axis; a first cylinderblock device positioned about said axis and having a contact face on oneside, cylinders in the other side and pistons in said cylinders, saidcontact face of the cylinder block device being in contact with one ofthe contact faces of the plate valve device; a first swash plate devicepositioned about said axis and pivotal with respect to said rotationalaxis about a pivotal axis transverse to the rotational axis and spacedto one side of the rotational axis, said swash plate device having apressure means operatively engaging said pistons whereby the pistonsurge the swash plate device in one direction of movement about saidpivotal ax s; first inclination adjusting means including a singleacting fluid operated linear motor means having a movable partoperatively engaging the swash plate device and movable parallel to therotational axis to urge the swash plate device in the opposite of saidone direction about said pivotal axis when fluid under pressure issupplied to said motor means; a second cylinder block device positionedabout said axis and having a contact face on one side, cylinders in theother side and pistons in said cylinders, said contact face of thesecond block device being in contact with the other of the contact facesof the plate valve device; a second swash plate device positioned aboutsaid axis and pivotal with respect to said rotational axis about apivotal axis transverse to the rotational axis and spaced to one side ofthe rotational axis, said second swash plate device having a pressuremeans operatively engaging the pistons of the second block devicewhereby the pistons urge the second swash plate device in a firstdirection of movement about its pivotal axis; second inclinationadusting means including a second single acting fluid operated linearmotor means having a movable part operatively engaging the second swashplate device and movable parallel to the rotational axis to urge thesecond swash plate device in the opposite of said first direction aboutsaid pivotal axis when pressure is applied to the second motor means;one of said first devices being connected to the driving shaft; one ofthe second devices being connected to the driven shaft; said devices,said shaft means and said frame being so interconnected that there isrelative rotation between the valve plate device and the two cylinderblock devices; and fluid control means connected to the two motor meansto adjustably position the position of the respective movable partsthereof and thereby set the position of the respective swash platedevice about their pivotal axes and thus the inclination of therespective pressure means with respect to the rotational axis.

23. A transmission as set forth in claim 22, including positioning meansconnected to the first cylinder block device and positioning meansconnected to the second cylinder block device to control the relativerotational positions of the block devices.

24. A transmission as set forth in claim 23, wherein each positioningmeans includes a housing engaging the respective cylinder block deviceloosely with clearance to permit the contact faces of the cylinder blockdevices to align with the respective faces of the slide plate valvedevice.

25. A transmission as set forth in claim 23, wherein the positioningmeans of the first cylinder block device also is connected to thedriving shaft for rotation therewith, and the positioning means of thesecond cylinder block. device also is connected to the frame to hold thelatter stationary, said swash plate devices and said slide plate valvedevice being connected to the driven shaft for rotation therewith.

26. A transmission as set forth in claim 25, wherein said driven shafthas a longitudinal groove along one side thereof and extending betweenthe two inclination adjusting means, said control means includes ahollow slide means positioned in said groove and movable longitudinallytherein, means to supply fluid under pressure to said slide, passagemeans at each end of the slide means communicating with the respectivemotor means, said slide means acting to control the flow of fluid to themotor means depending upon the relative position of the slide withrespect thereto, and means operatively connected to said slide means andexternally operable 2.2 to adjust the axial position of the slide meansand thus the flow of fluid for the motor means.

27. A transmission as set forth in claim 26, wherein said meansoperatively connected to said slide includes a shaft extending throughand journaled in the second cylinder block device, the two swash platedevices and the slide plate valve device have keys extending into saidgroove, said second cylinder block device has an operating oil channelextending radially therethrough, and said transmission includes an oilpump connected to deliver oil to said channel.

28. A transmission as set forth in claim 26, wherein each of said motormeans includes an adjusting cylinder longitudinally fixed with respectto said shaft means and an adjusting piston in said cylinder, saidadjusting pistons being movable axially of said shaft means and beingsaid movable parts, each adjusting piston including a closed boredefining a control cylinder aligned with the slide, each also includinga passageway communicating with said bore at a point spaced from theclosed end thereof and communicating with the respective adjustingcylinder, and said slide means includes an enlarged head on the endsthereof adjacent said bores, said heads being of a size to serve as apiston in said control cylinders and of an axial length to close thebore ends of the passageways.

29. A transmission as set forth in claim 23, wherein the positioningmeans of the first cylinder block device is connected to the drivingshaft, the positioning means of the second cylinder block device isconnected to the driven shaft, the slide plate valve device is attachedto said frame, said shaft means includes a dead shaft secured to theslide plate valve device, said cylinder block devices are jonrnaled onsaid dead shaft, and said in clination adjusting means are connected tosaid dead shaft.

30. A transmission as set forth in claim 29 and including an oil pump tosupply operating oil, and wherein said slide plate valve device has aradial conduit oommunicating with said pump to receive the operatingoil, said dead shaft has a longitudinal groove along one side thereofand extending between the two inclination adjusting means, said controlmeans includes slide means positioned in said groove and movablelongitudinally therein, said slide plate valve device has meanscommunicating with said conduit and with said slide means to supply oilto the slide means, said control means has passage means at each end ofthe slide means communicating with the respective motor means, saidslide means acting to control the flow of fluid to the motor meansdepending upon the relative position of the slide means with respectthereto, and means operatively connected to said slide means andexternally operable to adjust the axial position of the slide means andthus the flow of fluid for the motor means.

31. A power transmission comprising in combination: a frame; pump meansto supply operating oil; rotatable shaft means defining a rotationalaxis and having a longitudinal groove therein; a slide plate valvedevice positioned about said shaft and having a contact face normal tosaid axis; cylinder block device positioned about said axis and having acontact face on one side, cylinders in the other side and pistons insaid cylinders, said contact face of the block device being in contactwith the contact face of the plate valve device; a swash plate devicepositioned about said axis and pivotal with respect to said rotationalaxis about a pivotal axis transverse to the rotational axis, said swashplate device having pressure means operatively engaging said pistons;inclination adjusting means opcratively engaging the swash plate deviceto control the inclination of said pressure means, said adjusting meansincluding a single acting cylinder member and a piston member concentricwith said axis, one of said members being axially movable and the otherof said members being restrained against 23 a V 24 a a axial movement,said movable member being operatively means to control the position ofthe slide to control the connected to said swash plate device; andcontrol means iti f bl b communicating with said adjusting cylinder toadjustably position the position of the movable member and there-References Qited in the file of this patent by set the inclination ofthe pressure means of the swash 5 UNITED STATES PATENTS plate devlce,said control means including a hollow shoe in said groove, said slidecommunicating with said pump 5 1 Rose Allg- 1945 means and being movablelongitudinally to control the 2,453,123 HautZeIlfOedEl N V- 9, 1948 flowof oil therethrough to said adjusting cylinder, and 2,619,041 Born Nov.25, 1952

31. A POWER TRANSMISSION COMPRISING IN COMBINATION: A FRAME; PUMP MEANSTO SUPPLY OPERATING OIL; ROTATABLE SHAFT MEANS DEFINING A ROTATIONALAXIS AND HAVING A LONGITUDINAL GROOVE THEREIN; A SLIDE PLATE VALVEDEVICE POSITIONED ABOUT SAID SHAFT AND HAVING A CONTACT FACE NORMAL TOSAID AXIS; CYLINDER BLOCK DEVICE POSITIONED ABOUT SAID AXIS AND HAVING ACONTACT FACE ON ONE SIDE, CYLINDERS IN THE OTHER SIDE AND POSITIONS INSAID CYLINDERS, SAID CONTACT FACE OF THE BLOCK DEVICE BEING IN CONTACTWITH THE CONTACT FACE OF THE PLATE VALVE DEVICE; A SWASH PLATE DEVICEPOSITIONED ABOUT SAID AXIS AND PIVOTAL WITH RESPECT TO SAID ROTATIONALAXIS ABOUT A PIVOTAL AXIS TRANSVERSE TO THE ROTATIONAL AXIS, SAID SWASHPLATE DEVICE HAVING PRESSURE MEANS OPERATIVELY ENGAGING SAID PISTONS;INCLINATION ADJUSTING MMEANS OPERATIVELY ENGAGING THE SWASH PLATE DEVICETO CONTROL THE INCLINATION OF SAID PRESSURE MEANS, SAID ADJUSTING MEANSINCLUDING A SINGLE ACTING CYLINDER MEMBER AND A PISTON MEMBER CONCENTRICWITH SAID AXIS, ONE OF SAID MEMBERS BEING AXIALLY MOVABLE AND THE OTHEROF SAID MEMBERS BEING RESTRAINED AGAINST AXIAL MOVEMENT, SAID MOVABLEMEMBER BEING OPERATIVELY CONNECTED TO SAID SWASH PLATE DEVICE; ANDCONTROL MEANS COMMUNICATING WITH SAID ADJUSTING CYLINDER TO ADJUSTABLYPOSITION THE POSITION OF THE MOVABLE MEMBERND THEREBY SET THEINCLINATION OF THE PRESSURE MEANS OF THE SWASH PLATE DEVICE, SAIDCONTROL MEANS INCLUDING A HOLLOW SLIDE IN SAID GROOVE, SAID SLIDECOMMUNICATING WITH SAID PUMP MEANS AND BEING MOVABLE LONGITUDINALLY TOCONTROL THE FLOW OF OIL THERETHROUGH TO SAID ADJUSTING CYLINDER, ANDMEANS TO CONTROL THE POSITION OF THE SLIDE TO CONTROL THE POSITION OFTHE MOVABLE MEMBER.